Abstract: An IV fluid flow control device includes a rigid casing defining a flow passage having a fluid entrance and a fluid exit. A rigid, previous base is affixed inside the flow passage of the casing. A flexible, resilient flow regulator is disposed inside the flow passage of the casing adjacent to and upstream of the base. The flow regulator normally has a smaller cross-section than does the flow passage, leaving open space for fluid to pass. A rigid, previous cap is disposed inside the flow passage of the casing adjacent to and upstream of the flow regulator. The cap is axially movable inside the flow passage of the casing. The flow regulator biases the cap against pressure from fluid entering through the fluid entrance. Increases beyond a threshold level in the pressure from fluid entering through the fluid entrance cause axial compression of the flow regulator, thereby expending the transverse cross-section of the flow regulator, resulting in a reduction of the open space for fluid to pass.